fluid-sim/src/main/java/electrosphere/opencl/CLPlatform.java

package electrosphere.opencl;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.IntBuffer;
import java.nio.LongBuffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

import org.lwjgl.PointerBuffer;
import org.lwjgl.opencl.CL;
import org.lwjgl.opencl.CL30;
import org.lwjgl.opencl.CLCapabilities;
import org.lwjgl.system.MemoryStack;

/**
 * An object that encapsulates an openCL platform
 */
public class CLPlatform {
    
    //the id of the platform
    long id;

    //the capabilities of the platform
    CLCapabilities caps;
    
    //Information about the platform
    String vendor;
    String name;
    String version;

    // the list of all cl devices on this platform
    List<CLDevice> clDevices;

    /**
     * Creates a platform object
     * @param id The id of the platform
     */
    protected CLPlatform(long id, CLCapabilities caps, String vendor, String name, String version, List<CLDevice> clDevices){
        this.id = id;
        this.caps = caps;
        this.vendor = vendor;
        this.name = name;
        this.version = version;
        this.clDevices = clDevices;
    }


    /**
     * Gets a set containing all currently available platforms
     * @return The set containing all currently available platforms
     */
    public static Set<CLPlatform> getPlatforms(){
        Set<CLPlatform> platforms = new HashSet<CLPlatform>();

        try(MemoryStack stack = MemoryStack.stackPush()){
            //check if there are any platforms
            IntBuffer pi = stack.mallocInt(1);
            CLUtilities.checkCLError(CL30.clGetPlatformIDs(null, pi));
            if (pi.get(0) == 0) {
                throw new IllegalStateException("No OpenCL platforms found.");
            }
            //if there are platforms, get all platform IDs
            PointerBuffer platformIDs = stack.mallocPointer(pi.get(0));
            CLUtilities.checkCLError(CL30.clGetPlatformIDs(platformIDs, (IntBuffer)null));

            //add all platforms to the returned list
            for (int i = 0; i < platformIDs.capacity(); i++) {
                //get basic identification
                long platformId = platformIDs.get(i);
                CLCapabilities caps = CL.createPlatformCapabilities(platformId);
                String vendor = CLUtilities.getPlatformInfoStringUTF8(platformId, CL30.CL_PLATFORM_VENDOR);
                String name = CLUtilities.getPlatformInfoStringUTF8(platformId, CL30.CL_PLATFORM_NAME);
                String version = CLUtilities.getPlatformInfoStringUTF8(platformId, CL30.CL_PLATFORM_VERSION);


                //get devices on the platform
                int errcode = CL30.clGetDeviceIDs(platformId, CL30.CL_DEVICE_TYPE_GPU, null, pi);
                List<CLDevice> devices = new LinkedList<CLDevice>();
                if(errcode != CL30.CL_DEVICE_NOT_FOUND){
                    CLUtilities.checkCLError(errcode);
                    PointerBuffer deviceIDs = stack.mallocPointer(pi.get(0));
                    CLUtilities.checkCLError(CL30.clGetDeviceIDs(platformId, CL30.CL_DEVICE_TYPE_ALL, deviceIDs, (IntBuffer)null));
                    for (int j = 0; j < deviceIDs.capacity(); j++) {
                        long deviceId = deviceIDs.get(j);
                        devices.add(new CLDevice(deviceId));
                    }
                }

                platforms.add(new CLPlatform(platformId, caps, vendor, name, version, devices));
            }

            if (platforms.isEmpty()) {
                throw new IllegalStateException("No OpenCL platform found.");
            }
        }

        return platforms;
    }

    /**
     * Gets the id of the platform
     * @return the id of the platfomr
     */
    public long getId(){
        return id;
    }

    /**
     * Gets the capabilities object of the platform
     * @return The capabilities
     */
    public CLCapabilities getCapabilities(){
        return caps;
    }

    /**
     * Gets the name of the vendor the platform
     * @return The name of the vendor of the platform
     */
    public String getVendor(){
        return vendor;
    }

    /**
     * Gets the name of the platform
     * @return The name of the platform
     */
    public String getName(){
        return name;
    }

    /**
     * Gets the version of opencl on the platform
     * @return The version of opencl on the platform
     */
    public String getVersion(){
        return name;
    }

    /**
     * Gets the list of cl devices on this platform
     * @return The list of devices
     */
    public List<CLDevice> getCLDevices(){
        return clDevices;
    }

}